1. Field of the Invention
The present invention relates to a combustion engine equipped with an electrically operated throttle device.
2. Description of the Prior Art
An electrically operated throttle device used in motor vehicles such as, for example, motorcycles for controlling the air flow within an air intake passage has hitherto been suggested, which includes a throttle body defining in the air intake passage therein, a throttle valve accommodated within the throttle body for adjusting the cross section of the air intake passage, and an actuator for driving the throttle valve between a substantially closed position and a full open position and positioned in a lower portion of the throttle body. This known electrically operated throttle device is disclosed in, for example, the Japanese Laid-open Patent Publication No. 2006-214293.
According to the above mentioned Japanese publication, the known electrically operated throttle device is provided with a cooling unit for introducing a part of the intake air flowing through the air intake passage towards the actuator to cool the latter. It has, however, been found that the use of the cooling unit requires a portion of the air intake passage to be modified, or otherwise, renovated, to accommodate the cooling unit in the air intake passage and, therefore, the electrically operated throttle device as a whole tends to become complicated in structure.